Apparatus for indicating and recording contours of interior surfaces of tubes



Jan. 10, 1939.

. I F. L. WALLACE 2,143,233 APPARATUS FOR INDICATING AND RECORDINGCONTOURS OF INTERIOR SURFACES OF TUBES Filed Dec. 21, 1937 5Sheets-Sheet l FRANK L..WALLACE INVENTOR ATTORNEY Jan. 10, 1939. F.WALLACE 2,143,233

APPARATUS FUR INDICATIHG AND RECORDING CONTOURS OF INTERIOR SURFACES OFTUBES Filed Dec. 21, 1937 3 Sheets-Sheet 2 O FRANK L. WALLACE INVENTORBY m 1 13,441 ATTORNEY mdi Patented Jan. 10, 1939 UNITED STATESAPPARATUS FOR. INDICATING AND RECORD- ING CONTOURS OF 0F TUBES INTERIORSURFACES Frank L..Wallace, Port Arthur, Tex, assignor to The TexasCompany,

notation of Delaware New York, N. Y., a cor- Application December 21,1937, Serial No. 180,974

5 Claims.

This invention relates to apparatus for indicating and recording thecontour of the interior surfaces of tubes, and concerns particularly anapparatus adapted to indicate and re- 5 produce, in cross section, theexact contour of the interior surfaces of a tube or similar article at apoint located at any distance from -the ends thereof. The apparatus ofthe invention isparticularly useful for determining the contour of H)the interior surfaces of tubes used in tube stills for cracking oil.

As is known in the oil refining art, theoil to be processed isintroduced into a series of relatively long tubes suitably joinedtogether to form a tortuous conduit of relatively great length.Throughout a? substantial portion of this conduit the oil is subjected,under considerable pressure, to relatively intense heat from a furnace.Under the working conditions, with the high temperatures on one side ofthe tube and the pressure of the oil on the other side, together'withthe reacting components contained in the oil, the tubes are subjected towhat is generally conceded to be relatively severe service. In practicethe tubes have a tendency to swell or to be pitted and eaten away atcertain, points due to erosion, chemical action or for other reasonsZ.It is of course readily appreciated that the failure, under operatingconditions, of a tube with the conse-' quent releasing of the pressureand of the contained' oil into the furnace is a serious matter.Accordingly, all precautions are usually exercised which are possible toavoid such an occurrence and, in this connection, the furnaces are shutdown periodically and the tubes examined. Heretofore the inspector hasbeen compelled to confine his observations substantially to those tubeswhich could be visually inspected from the outside inasmuch as there hasbeen no known instrument available for measuring and recording thecontour.of the interior surfaces of the tubes throughout their length.In this connection it is to be pointed out'that the tubes are usuallyseveral feet in length, in some instances extending for lengths of from5 to 30 feet.

While I shall describe the apparatus of the invention in connection withits. use for determining the contour of the interior surfaces of tubesused in tube stills for cracking oil, it will be understood that theapparatus may be used also 'for many other purposes.

In the oil fields the'device can be used for calipering slush pumpliners, as a reading can be obtained which can not be obtained by handcalipering with any reasonable expenditure of time.

The device can be used to caliper oil well liner pump barrels todetermine whether they should be reworked or not. It can also be used onthe plunger barrel to determine what repairs are necessary.

Tubular goods used in drilling, such as kellys, drill collars and drillpipe, can be checked by this device to, determine whether any largeamount of fluid cutting has occurred either during regular drilling orduring a short blow-out.

The device can be used in internal upset drill pipe, for checking up onthe condition of the pipe just below the upset. No satisfactory meansfor doing this has been available heretofore.

In accordance with the invention the apparatus includes a detecting andtransmitting device adapted to be inserted in the tube to be measuredand an indicating and recording device which ordinarily is situatedoutside the tube. The detecting device is adapted to be rotated with inthe tube and includes a tracing unit which is adapted to engage andtrace the contour of the interior surface of the tube as the detectingdevice is rotated. It also includes the transmitting motor of a pair ofSelsyn motors. The tracing device actuates the shaft of the motor sothat the shaft is deflected slightly by any irregularities in thecontour of the interior surfaces of the tube.

The recording device includes the receiving or indicating motor of thepair of Selsyn motors. The Selsyn motors operate ontheprinciple ofmagnetic linkage, a deflection of the rotor of one motor producing anexact deflection in the rotor of the connecting motor both as to degreeand direction. Thus, any deflections in the shaft of the transmittingmotor are communicated to the shaft ,of the receiving motor, which iscorrespondingly deflected.- The shaft of the receiving motor actuates apen arm and any deflections in that shaft arerecorded on a chart bymeans of the pen arm. The chart is rotated automatically at the samespeed as the detecting device is rotated, so that the record on thechart corresponds exactly to the contour of the interior surfaces of thetube being examined.

The invention will be better understood from the following descriptionand the accompanying drawings. Referring to the drawings:

Figure 1 is a view in elevation, partly in sec tion, of apparatusembodying this invention.

Figure 21s a 'view on an enlarged scale of the Figure i is a. view on astill larger scale of the tracing apparatus shown in the lower portionof Figure 3.

Figure 5 is a plan view taken on the line 5-5 of Figure 4.

Figure 6 is a plan view taken on the line 6-6 of Figure 2.

Figure '7 is a tracing of an actual recording.

showing the contour of a heating tube, which tracing was made withapparatus substantially as described herein.

Figure 8 is a chart which may be used as a guide for comparing thecontour of the tube examined with that of a tube having the desireddimensions. 1

Referring to Figure 1, the apparatus is shown fully assembled and inposition for recording the contour of the interior surfaces of a heatingtube. A portion of a heating tube in is'shown, this tube beingrepresented as situated in a heater in which the heating tubes thereofare positioned vertically. A return bend fitting H, which ordi- 1 narilyis used for securing the end of the tube ill to a U-bend, rests upon andis supported by a tube sheet i2. The return bend fitting II is providedwith an insert or collar l4 in which the end of the tube i0 is securedby upsetting the tube as at I5, and which is tapered as at t6'to engagethe tapered portion of a U-bend.

A detecting and transmitting unit indicated enerally as, at l! is showninserted in the tube by a centering'device 2| which engages the walls'of the tube I 0 and provides a bearing for the pipe H3. The clampingdevice i9 permits the unit I? and the pipe |8 to be advanced within thetube 8 so that additional examinations may be made.

The arrangement is such that the unit I! may be rotated in the tube In,by rotating the pipe l8 to whichit is secured. A chart holder 22 isconnected by-means of gears to the pipe i 8, so that it will becorrespondingly rotated upon rota tion of the pipe i8. The detectingunit I! includes a tracing device 23 which is adapted .to trace thecontoiu of the interior surfaces of the tube l0 as the unit I! isrotated. The unit I! also includes the transmitting motor 24 of a pairof Selsyn motors and the tracing device 23 actuates the shaft of themotor so that said shaft is deflected or rotated slightly by anyirregularities in the contour of the tube Ill. The recording device 28includes the receiving motor 25 of said pair of Selsyn motors. Thestators of the two motors .24 and 25 are connected togetherelectricallyand the rotors are energized by an alternating current voltage in a'manner well known to those familiar with self-synchronous motors. Anydeflections in the shaft of the transmitting motor 24 are thuscommunicated to. the shaft of the receiving motor 25 which is deflectedin exactly the same way. The shaft of the receiving motor 25 actuates apen arm 26 and any deflections in the shaft of the motor 25 are recordedby the pen arm on a chart which isheld by the chart holder 22.

Referring to Figures 4 and 5, a bracket 21,

which'is rigidly secured to the-lower end of the transmitting motor 24,supports the tracing device 23. The latter device includes a tracing arm28 which is secured to the bracket 21 by means of a pin 29, the'pin 29forming a pivot 1 about which the tracing arm 28 may be rotated.

A spring 38 shown in Figure 4 attached tothe bracket Ti and arm 28forces the tracing arm outwardly, or upwardly as viewed in Figure 5,

against the walls of the tube l8. arm 28 is shown as generallytriangular in shape and the sidethereof opposite the pin 29 is pref- Thetracing erably curved and provided with a groove 3|.

A slot 3| 0. is also formedin the arm 28. A guide 32 is rigidly securedto the bracket 21, this guide having a curved side adjacent the tracingarm 28, and being provided with a tongue 33 which engages the groove 3|in the tracing arm 28. The guide 32 thus assists in supporting thetracing arm 28 during rotation thereof. A contact member 34, which isadapted to engage the walls of the tube i0, is secured to one edge orcorner of the tracing arm 28. The contactmember 34 is shown as a smallplate pivotally mounted on the arm '28 and having two points 3411 and3417. In case one point becomes worn, the plate can be turned by meansof a thumb nut 340 so as to bring the other point into proper position.A gear segment 35 is secured to or formed on the tracing arm 28 on theside of the slot 3|a' opposite the pin 29. The gear segment 35 engages apinion gear 36 which is secured to the shaft of the transmitting motor24 and which projects into the slot 3|a.

In operation, the detecting and transmitting unit H, including thetransmitting motor 24 andthe tracing device 23, are slowly rotated byhand through 360 degrees in the tube Ill. The point 34a on thetracingarm 28 follows the contour of the interior surfaces of the tubeduring the rotation of the unit I1. Since the gear segment 35, which issecured to the tracing arm 28, engages the pinion gear 36, the'shaft ofthe transmitting motor 24 which is secured to-the pinion gear 36 isthereby deflected slightly according to any irregularities in thecontour of the tube in.

Referring now to Figure 3, a ring-shaped member or bracket 31 is rigidlysecured to the upper side of the transmitting motor 24, this bracketbeing rigidly secured also to a pipe 38 which is an extension of thepipe l8. The pipe 38 is relatively short and is connected to .the pipeI8 by a pipe coupling 39.

The centering device 2| includes a sleeve 46 which surrounds the pipe38. The sleeve is threaded at the lower end thereof to receive acollar'and, as shown in the drawings, the collar against a collar 45which likewise surrounds the sleeve 40 but is longitudinally movablethereon. The collar 45 engages cams 46 which form a part of the fingers43, therebyforcing said fingers outwardly against the walls of the tube10. The

fingers 43 are provided with rollers 41 which engage the walls of thetube Ill, these fingers thus serving to maintain the detecting devicecentered in the tube, the contour of which is to be recorded.

Referring to Figures 2 and 6, the clamping device i9 includes a lowerdisc-shaped member 48 in which a plurality of radially disposed channels49 are formed. The channels 49 are adapted to receive clamping dogs 50.The clamping dogs are provided with shoulders 5! which engage the wallsof the channels 49 so thatsaid dogs are slidable in said channels, anddepending portions 52 which are adapted to engage the upper portion ofthe return bend fitting II .when

said dogs are expanded outwardly in said chan nels. The clamping devicel9 also includes an upper disc-shaped member 53, this member beingprovided with curved slots 54 adapted to receive pins 55 secured to theclamping dogs 50. Upon rotation of the disc-shaped member 53 the slots54 expand the dogs 50 outwardly in the channels 49, into engagement withthe upper portion of the return bend fitting H. member 53 is providedwith a handle 56 which may be used for rotating it.

An upwardly extending nipple 51 is secured to the disc-shaped member,this nipple being threaded at 58 to receive a collar 59. A horizontalextension 60, which is used to support the recording device 20, issecured to the collar 89. A ring-shaped bearing member 6|, which is'usedto support the pipe l8 so thatit may b rotated, also is secured tothecollar 59.

A pair of clamping members 62, shown more clearly in Figure 6, which maybe quickly fasten'ed around the pipe I! and easily disengaged therefrom,are used to support the pipe It so that said pipe may be advanced intothe tube In. The clamping members 62 are pivoted at one side to boltswhich secure them to -an annular member 63. The member 63- is adapted tobe rotated in the bearing member SI and a hinged bolt 64 is used tofasten the clamping members 62 around the pipe It.

.A gear 65 is secured to or formed on the.

annular member '3. The gear '65 is used, together with a second gear 66which is secured to the chart holder 22, to rotate said chart holderwhen the pipe II. is rotated. The chart holder 22 and the gear, 86 aresecured to opposite ends of a sleeve '1, this sleeve 61 surrounding andadapted to be rotated upon a vertical pin 68. The pin 8 is secured tothe horizontal extension SI and has a shoulder which provides a bearingfor the lower end of the sleeve 61. The pin 64 is threaded to receive anut 69 which secures the sleeve 61 against removal from said pin.

A bracket 10 which is in the form of an inverted U and which straddlesthe chart holder 22 is supported upon extension 64 and in turn supportsthe recording unit 20. The recording unit II is in many respects similarto the detecting and transmitting unit l1, above described. Thereceiving motor 25 is supported directly upon the bracket I. and isconnected to the transmitting motor 24- by a flexible cable ll whichpasses through the pipe ii. .A branch H a of the cable H may beconnected to a suitable source of alternating current to energize therotor windings of the motors 24 and 25. The receiving motor 25 is,provided at the lower end thereof with a pinion gear (not shown) whichis similar to the pinion gear 38 of the detecting unit. The pinion gearengages a gear segment which is tion.

The disc-shaped similar to the gear segment 35 of the detecting unit,thereby actuating a member I2- which corresponds to the tracing arm 28of the detecting and transmitting device. The member 12 is rigidlysecured to a pin 13, and travels in a guide The pin 13 extendsdownwardly through a bearing 15 which is formed in the bracket 10 and isrigidly secured at its lower end to the pen arm It.

It is believed that the operation of the apparatus will be clear fromthe foregoing descrip- However, in summarizing, the detecting 14, theguide being secured to the bracket 10.

and transmitting unit I1 is placed in the-tube, Y

the inner contour of which is to be recorded, and the clamping device I9is adjusted so that the tracing arm '28 will be at the proper distancefrom the end of the tube. A blank chart such as is shown at 16 in Figure7 is secured to the chart holder 22 and the pen arm 26 adjusted to makecontact with the chart. The unit I! is then rotated slowly by turningthe pipe I! through 360 degrees. The tracer point 34a will follow theinterior surface of the tube and through the arm 28 and the gearing 35and 36 will cause the rotor of the motor 24 to be defiected or rotatedslightly in accordance with any irregularities in the contour of thetube surface being examined. Due to the magnetic linkage between themotors 24 and 25, the pen arm will move on the chart at the same timeand to the same extent as the tracer arm 28 is moved. Becauseof thegearing connection 65 and 66 the chart holder 22 will revolvesimultaneously with the detecting unit and the tracing 11 of the pen onthe chart will therefore coincide exactly with the interior surface ofthe tube being examined.

Figure 7 represents an actual tracing showing the cross-section of atube which has undergone spotty corrosion. The chart 16 on which thesection of the tube calipered is recorded may be made of transparentpaper, thus making it possible to superimpose the contour 11 of the tubeon the master chart for that particular size tube such as is shown inFigure 8, thus by comparison the extent of pitting or corrosion of theinterior tube surface will be clearly indicated.

As has been stated hereinbefore, it is to be understood that thisapparatus is not limited to use in examining the interior surfaces ofstill tubes. The interiors of various kinds of holes may be readilystudied in a similar manner since it is merely necessary to clamp theshaft supporting the detecting and transmitting unit in proper positonwithin the hole to be examined.

Obviously many modifications and variations of the invention may be madewithout departing from the spirit and scope thereof, and therefore onlysuch limitations should be imposed as are indicated by the appendedclaims.

I claim:

1. An apparatus for indicating the'contour of the interior surface of atube, comprising 'a detecting unit adapted to be positioned and rotatedwithin the tube, said detecting unit including one of 'a pair ofelectrical self-synchronous motors, a tracer arm connected to the rotorshaft of said motor and adapted to engage and follow the interiorsurface of said tube as the motor is rotated in the tube, an indicatingunit including the second of a pair of self-synchronous motors, saidsecond motor being rigidly mounted exteriorly of said tube, and 'anindicating arm secured to the rotor of said second motor, saidpair ofmotors 1g being electrically interconnected so that as said detectingdevice is rotated within the tube, deflection of said tracer arm willproduce corresponding deflections of said indicating arm.

2. An apparatus for indicating the contour of the interior surface of atube, comprising a detecting unit adapted to be positioned and rotatedwithin the tube, said detecting unit including one of a pair. ofelectrical' self-synchronous motors, atracer arm connected to the rotorshaft of said motor and adapted to contact with and follow the interiorsurface of said tube as the motor is rotated-in the tube, an indicatingunit including .the second of the pair ofself -synchrono us motors,'saidsecond motor being rigidly mounted exteriorly of said tube, a chartholder having a chart aflixed thereto, gearing between said chart holderand said detecting unit for rotating said chart holder in synchronismwith the rotation of said detecting unit, a pen arm secured to the rotorof said second motor and in contact with said chart, said pair of motorsbeing electrically interconnected so that as said detecting device isrotated within the tube, deflection of said. tracer arm will producecorresponding deflections of said pen arm so as to trace on said chartthe interior contour of said tube.

3. An apparatus for indicating the contour of the interior surface of atube, comprising a detecting and transmitting unit adapted to bepositioned and rotated within the tube, said detecting and transmittingunit comprising one of a pair of electrical self-synchronousmotors, apipe member secured to said motor and adapted to support said ,motor inoperative position within the tube, means for clamping said pipe memberto said tube so that the-pipe and motor may be rotated with respecttosaid tube, means cooperating with said clampingmeans for maintainingsaid pipe and motor concentric with respect to said tube, a tracer armconnected tothe rotor shaft of said motor and adapted to engage'andfollow the interior surface of said tube as the motor is rotated inthetube, an indicating unit including the second of a pair ofself-synchronous motors-and an indicating arm secured to'the rotor ofsaid second motor, said pair of motors being electrically interconnectedso that as said detect; ing and transmitting device is rotated withinthe tube, deflection of said tracer arm will produce correspondingdeflections of said indicating arm.

4. An apparatus for indicating the contour of the interior surface of atube comprising a pair of electrical self-synchronous motors, electricalconnections between said motors so that as the rotor of one motor isrotated, the rotor of the other motor will be correspondingly rotated, atracer arm secured to the rotor of the first motor and an indicating armsecured to the rotor of the second motor, means for supporting saidfirst motor within and concentrically of the tube with said tracer armengaging the interior surface of the tube, and means for rotatingsaid-first motor within the tube while said tracer arm follows theinterior contour of the tube, the arrangement being such that as saidfirst motor isrotated movements of said tracer arm caused byirregularities of the interior surface of the tube will causedeflections of the rotor of said first motor and said rotor deflectionswill cause corresponding deflections of the rotor and indicating arm ofthe second motor.

5. An apparatus for indicating the contour of the interior surface of atube comprising a pair of electrical self-synchronous motors, electricalconnections between said motors so that as the rotor of one motor isrotated, the rotor of the other motor will be correspondingly rotated, atracer arm secured 'to the rotor of the first motor and an indicatingarm secured to the rotor of the second motor, means for supporting saidfirst motor within and concentrically of the tube with said tracer armengaging the interior surface of the tube, and means for rotating-saidfirst motor within the tube while said tracer arm follows the,

interior contour of the tube, means for rigidly supporting said secondmotor exteriorly of said tube, a marking device secured to saidindicating arm, a chart holder having a chart aflixed thereto andadapted to be contacted by said marking device, gearing between saidchart holder and the supporting means for the first motor so that saidchart holder and chart will be rotated in synchronism with said firstmotor whereby movements of said tracer arm caused by irregularities inthe inner surface of said tube will be transmitted to the indicating armof said second motor to cause said marking device to trace on said chartthe interior contour of said tube.

FRANK L. WALLACE.

